On the Genus Isoetes. 



125 



In the year 1855 Messrs. Grenier and Godron published their 

 excellent " Flora of France and Corsica," in which they described 

 all the Isoetes found within those limits. The species are there 

 divided into three sections : — 



1. — Aquaticce, containing our north of England species 



I.palustris only. 



2. —Palustres, comprising three species not found in 



Britain. 



3. — Terrestres, comprising /. hystrix and I. Durioei. 



It seems very probable that Mr. George Wolsey, who dis- 

 covered our plant on PAncresse Common in 1860, must have 

 seen a copy of this work and then searched specially in the 

 likeliest places. If not, he must certainly have stumbled upon 

 the plant by accident, for at that date a terrestrial Isoetes was 

 as undreamt of as a terrestrial Chara. However the plant was 

 found and submitted to Sir John Hooker who named it Isoetes 

 Durioei, whilst Professor Babington who also had specimens 

 sent to him, pronounced it to be I, hystrix. That it was per- 

 fectly distinct from the two aquatic species known in the 

 British Isles, namely I, lacustris and /. echinosjpora was at 

 once apparent by the root stock or corm being covered with 

 jagged or spinous brown scales, which are never present in the 

 water forms. 



Now the distinction between the two species to which the 

 Guernsey plant was referred seems, in the books at least, to be 

 anything but clear. The i. hystrix of Durieu has the bulb sur- 

 rounded by short black shining scales, terminated by two long 

 linear subulate horns or spines, one-third of an inch in length, 

 between which often appears a third one, very short. In I, 

 Durioei of Bory, the scales were very short, black, with three 

 teeth and no spines. 



Lloyd in his " Flore de l'ouest de la France " (a book by 

 the way which should be in the hands of every Channel Islands 

 botanist) says the two species approach very near to each other, 

 but in hystrix the macrospores are slightly granulated (Babing* 



